Torque delivery signal control mechanism for a two-speed nut-running tool

ABSTRACT

A nut-running tool having an initial rundown phase and a final torquing phase, accomplished by means of a main rundown air motor and an auxiliary torquing air motor, both operating concurrently in the same direction. The rundown motor operates through a small gear reduction connection in a planetary gear system to drive a common output spindle connected with the work; and the torquing motor acts through a larger gear reduction connection in the planetary gearing to drive the spindle. The rundown motor stalls on the gearing upon reaching the limits of its capacity, permitting continued torque delivery by the torquing motor until the holding capacity of the rundown motor on the gearing is reached. Thereafter, further torque delivery of the torquing motor acts through the gearing to rotate the rundown motor backwards. At about the time the main motor starts to rotate backwards, a final torque value is delivered by the auxiliary motor, after which the work does not experience further torque increase. The directional change of rotation is used to cause actuation of control mechanism which is operable to signal a circuit to terminate operation of the tool after delivery of final torque has occurred.

Unite [72] Inventor William K. Wallace Barneveld, N.Y.

[21] App]. No. 874,270

[22] Filed Nov. 5, 1969 [45] Patented June 15, 1971 [731 Assignee Chicago Pneumatic Tool Company New York, N .Y.

[54] TORQUE DELIVERY SIGNAL CONTROL MECHANISM FOR A TWO-SPEED NUT-RUNNING TOOL 7 Claims, 6 Drawing Figs.

[52] US. Cl 173/20, 81/52.5,173/12 [51] Int. Cl 1325b 23/14 [50] Field of Search l73/l2,20;

[56] References Cited UNITED STATES PATENTS 3,298,481 1/1967 Schaedler et al. 173/12 X 3,354,754 11/1967 Amtsberg et a1 81/524 3,387,669 6/1968 Wise et a1. 173/20 X 3,440,908 4/1969 States 81/52.4

Primary Examiner- Ernest R. Purser Attorney-Stephen J. Rudy ABSTRACT: A nut-running tool having an initial rundown phase and a final torquing phase, accomplished by means of a main rundown air motor and an auxiliary torquing air motor, both operating concurrently in the same direction. The rundown motor operates through a small gear reduction connection in a planetary gear system to drive a common output spindle connected with the work; and the torquing motor acts through a larger gear reduction connection in the planetary gearing to drive the spindle. The rundown motor stalls on the gearing upon reaching the limits of its capacity, permitting continued torque delivery by the torquing motor until the holding capacity of the rundown motor on the gearing is reached. Thereafter, further torque delivery of the torquing motor acts through the gearing to rotate the rundown motor backwards. At about the time the main motor starts to rotate backwards, a final torque value is delivered by the auxiliary motor, after which the work does not experience further torque increase. The directional change of rotation is used to cause actuation of control mechanism which is operable to signal a circuit to terminate operation of the tool after delivery offlnal-torque has occurred.

Ti I I 67 l 1 I 73 L I l I J PATENTED JUN] 5197:

SHEET 2 [IF 2 S, m ATTORNEY TORQUE DELIVERY SIGNAL CONTROL MECHANISM FOR A TWO-SPEED NUT-RUNNING TOOL BACKGROUND OF THE INVENTION This invention relates to signal control mechanism for use in association with a pair of air motors operating in a nut running tool with different value gear reduction connections through common planetary gearing to drive a common output spindle connected with the work. Its function is to issue a control signal when the motor having the smaller gear reduction connection is caused to rotate in a reverse direction by the torque being transmitted to the planetary gearing by the other motor.

Issuance of the control signal indicates that a predetermined value of torque has been applied to the work. The signal serves to establish a control circuit to cause termination of operating power to the tool.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIG. 1 is a longitudinal section through a two-speed nut runner embodying the invention;

FIG. 2 is a cross section of line 2-2 of FIG. 1;

FIG. 3 is a detail of the front face of the driving member of the slip clutch;

FIG. 4 is a section on line 4-4 of FIG. 3, but with the ring element and other components of the clutch added;

FIG. 5 is a detail of the rear face of the driving clutch member, but showing the body portion in section; and

FIG. 6 is a schematic view showing the pressure control chamber in a form having multiple outlets for control of a multiple number of nut runners.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The illustrated nut-running tool includes a general housing 10 in which is supported for relative rotation a main or run down air vane motor 42 and a separate auxiliary or torquing air vane motor 11. The motors are arranged in axial alignment with one another. Both motors are concurrently operable in the same direction to drive through a common planetary gear system 36 a common output carrier spindle 38 connected with the work 20. The main motor has a small gear reduction connection by means of a ring gear 37 with planet gears 34 of the gear system; and the auxiliary motor has a larger gear reduction connection by means of a sun gear 33 with the planet gears 34. The sun gear is carried at one end of an elongated shaft 32 coupled to the auxiliary motor. The shaft extends through a bore 55 of the rotor 43 of the main motor, and has relative rotation.

An inlet 58 connectable to an external source 50 of pressure air connects by means of a passage 62 with the rotor chambers of both motors. Air fed through the inlet causes both motors to operate concurrently and in the same direction. The main motor, because of its small gear reduction connection with the output spindle, serves to initially run down the work to an initial degree of tightness and stalls upon reaching the limits of its capacity. While stalled, it holds the ring gear 37 stationary. This enables the auxiliary motor 11 to thereafter continue further torque delivery to the work until the capacity of the main motor 42 to hold the ring gear stationary is exceeded. When this occurs, the torque being transmitted by the auxiliary motor to the gear system 36 acts to rotate the main motor 42 backwards. A final torque value is delivered to the work by the auxiliary motor 11 at about the time of change of directional rotation of the main motor.

The value of final torque delivered to the work can be regulated by changing the pressure of the operating air flowing to the main motor by means of an adjustable pressure regulator 64 interposed in the supply line 63.

The directional change of rotation of the main motor is used to actuate signal control mechanism 93 to close a control switch 65 (FIG. 2) in a signal device or electrical circuit 66. This will energize a solenoid 67 to close a valve 60 in the supply line 63 so as to shut off operating air to the tool. The control mechanism (generally indicated at 93 in FIG. 2) to effect this action, includes a pressure chamber 68 connected by a restricted flow line 69 to the pressure air source 50. When air pressure of a certain degree is caused to build up in chamber 68, it forces a plunger 71 against the bias of its return spring 72 to actuate the switch 65 to closed condition. During the time the main motor 42 is rotating in a forward direction and prior to its directional change of rotation, pressure air entering chamber 68 is unable to build up to actuate the plunger, since the entering pressure air is normally being vented through a valve unit 74 over a passage 73 of larger diameter than the line 69.

The valve unit 74 includes a bushing or fitting 75 extending through the sidewall of the housing 10 into the interior of the latter. A ball valve 76 is operable relative to a valve seat 77 in the bushing. In its open condition, as in FIG. 2, the ball valve normally floats within the confines of an annular skirt wall 78 of the bushing between the seat 77 and the opposed surface of a ring 79. The ring surrounds and is of slightly larger diameter than the cylindrical body 81 of a slip-clutch driving member 80, the slip-clutch being defined by the ring 79 and the member 80. A plunger 82, operating in a radial bore of the clutch body 81, is pressed by its spring load against the inner diameter surface of the ring so as to frictionally engage the latter with the clutch body 81. The clutch body has an eccentrically located bore 84, the inner wall of which surrounds the end of the shaft 52 of the main motor. A clutch ball operating in an open-ended slot 86, formed in the clutch body between the rotor shaft 52 and the ring 79, is biased by a spring 87 into contact with the opposed surfaces of the ring 79 and the rotor shaft 52.

In the operation of the control mechanism 93, assuming the shaft 52 is rotating in a clockwise direction delivering torque to the work, the control mechanism will at this time have a condition as in FIG. 2. In this condition, a shoulder 88 of a semicircular flange 89 on the clutch body 81 abuts a stationary stop pin 91 and thus restrains the clutch body 81 together with the ring 79 frictionally engaged thereto from rotating in a clockwise direction. At this time, the clutch ball 85 will have the position as in FIG. 2 wherein it will be biased by the light spring 87 into contact with opposed surfaces of the ring 79 and shaft 52. In this position of the clutch ball, the eccentric diameter of the clutch body 81 prevents the force of the spring-loaded plunger 82 from acting on the clutch ball so that the light frictional drag created on shaft 52 by the bias of the spring 87 on the clutch ball is ineffective to prevent clockwise rotation of the shaft 52 relative to the clutch body. While the shaft 52 is thus rotating in a clockwise direction, the low end of the eccentric defined by the clutch body 81 and ring 79 is sufficiently positioned from the ball valve seat 77 so as to allow air entering the pressure chamber 68 to vent around the unseated ball valve 76 and flow through the interior of the housing 10 to atmosphere.

When the rotor shaft 52 stalls with the main motor 42, as earlier explained, following the initial partial tightening of the work, the valve unit 74 remains in open condition, as in FIG. 2, allowing air to vent from the chamber 68 around the ball valve 76. At about the time final torque is delivered by the auxiliary motor 11 to the work, the rotor shaft 52 starts to rotate backwards in a reverse or counterclockwise direction with the main motor 42, as earlier explained. The reverse rotation of shaft 52 causes the clutch ball 85 to be rolled against the wall area 92 of slot 86 into a locking position between the ring 79 and shaft 52 subject to the load of the plunger 82. Shaft 52 thus becomes frictionally engaged with the clutch body 81 and ring 79 and carries them around with it. In this action, the shoulder 88 will be carried away from the stop pin 91; and the high end of the eccentric defined by the clutch body 81 and ring 79 will eventually be carried over the ball valve 76 to cam it closed upon its seat. This blocks venting of air from the pressure chamber 68 and thus enables air pressure to build up in the latter. The cammed condition of the ring 79 with the ball valve prevents further counterclockwise rotation of the ring and clutch body with shaft 52. In this respect, as the ring 79 obtains the cammed condition, it forces the plunger 82 into its bore, and shaft 52 continues rotating in the counterclockwise direction relative to the stopped ring and clutch body, slipping as it does so relative to the clutch ball 85. Shaft 52 continues this relative rotation until the pressure in chamber 68 builds up sufficiently to actuate the switch 65 to shut off further flow of operating air to the tool.

It is noted from FIG. 2 that it is only necessary for the ring 72 to be carried counterclockwise from the position wherein the ball valve 76 is in open condition for an angular distance of about l80 to cam the ball valve closed upon its seat. A brief time is then required for pressure to build up in chamber 68 to actuate the switch 65. By means of this arrangement, operating air to the tool is not immediately shut off at the start of the reverse rotation of the main motor and sufficient time is caused to elapse to make certain that final torque has been delivered to the work before the operating air has been shut off.

At the start of the next cycle of the tool, after trapped pressure air has been relieved in suitable manner from chamber 68 so as to allow the switch 65 to reopen, the ball valve 76 will nevertheless still be held cammed by ring 79 in closed condition and the clutch ball 85 will still be in its locking position against the wall area 92 subject to the forces of the plunger 32 and the spring 87. As shaft 52 rotates clockwise, it will be frictionally engaged by the clutch ball 85 with the ring 79 and clutch body 81 so as to carry them about with it causing the ball valve 76 to become unseated. The frictional drive continues until the shoulder $8 of the clutch body 81 engages the pin 91, preventing further rotation of the clutch body and ring. Shaft 52, however, continues rotating clockwise relative to the clutch body and ring as it causes the clutch ball to be rolled out of its locking position from the wall area 92 to the position shown in FIG. 2, free of the force of the spring loaded plunger 82.

The pressure chamber 68 may be made common to a plurality of nut running tools, the valve unit 74 of each of which would be connected by means of a separate vent line 73 to the pressure chamber 68, as appears in FIG. 6. The pressure chamber 68 would, in this instance, be vented through the valve 74 of each tool. In such an arrangement, when the valves 74 of all of the tools are finally closed, air pressure will then build up in the common chamber 68 to close the control switch 65 and thus simultaneously shut off operating air flow to all of the tools. It is understood in the case of multiple tools, that the inlet passage 58 of each tool would have a separate connection with the supply line 63 or with a common manifold connected to the supply line 63.

The flow through line 69 may be adjusted by means of a suitable feed valve 30 and a pressure regulator 70.

What I claim is:

1. In a rotary tool including a reversible rotary shaft, a presthe shaft when the shaft is rotated in a reverse direction to cam the valve closed over the vent, the slip-clutchcam means being adapted to slip relative to the shaft upon camming the valve closed so as to allow relative continued rotation of the shaft in the reverse direction.

2. In a rotary tool as in claim 1, wherein the actuable means isaspring-returnableplunger.

In a rotary too as 1n claim 1, wherein the mlet is of restricted diameter relative to the vent.

4. In a rotary tool as in claim 1, wherein the slip-clutch cam means is responsive to a change of rotation of the shaft from a reverse direction to said forward direction to rotate with the shaft so as to release the valve from its closed condition.

5. In a rotary tool as in claim 4, wherein stop means projects into the path of rotation of the slip-clutch cam means so as to stop rotation thereof in said forward direction after the slipclutch cam means has traveled a predetermined angular distance, the slip-clutch cam means being adapted to slip relative to the shaft when so stopped so as to allow relative continued rotation of the shaft in said forward direction.

6. In a nut-running tool including a reversible rotary shaft, a pressure-operable signal device, an air-pressure chamber, and actuating means adapted upon building up of a predetermined air pressure within the chamber to cause operation of the signal device, the pressure chamber having an inlet connectable to a source of pressure air and having a vent for preventing buildup of inlet air pressure within the chamber when the vent is in open condition, a valve seat at the exit end of the vent, a ball valve having a loose relation to the seat while the shaft is rotating in a forward direction so as to allow venting of pressure air from the chamber; cam means for pressing the ball valve closed upon the seat when the shaft is caused to rotate in a reverse direction, slip-clutch means frictionally engaging the shaft with the cam means for rotation of the cam means with the shaft, the slip-clutch means adapted upon a predetermined resistance being offered to rotation of the cam means to allow rotative slippage of the shaft relative to the cam means, the ball valve adapted upon being pressed closed upon the seat by the cam means to resist further rotation of the cam means by the shaft in said reverse direction.

7. In a nut-running tool as in claim 6, wherein the slip-clutch means is responsive to a change of rotation of the shaft from a reverse direction to a forward direction so as to cause the shaft to carry the cam means angularly out of said pressed relation to the ball valve, an ear projects from the cam means, and a stop having cooperation with the ear following a predetermined angular movement of the cam means with the shaft resists further angular movement of the cam means with the shaft in the said forward direction. 

1. In a rotary tool including a reversible rotary shaft, a pressure-operable signal device, an air-pressure chamber, and actuable means adapted upon building up of air pressure within the chamber to cause operation of the signal device, the pressure chamber having an inlet connectable to a source of pressure air and having a vent for preventing buildup of inlet air pressure within the chamber when the vent is in open condition; a valve positionable to allow escape of pressure air from the chamber through the vent while the shaft is rotating in a forward direction, and slip-clutch cam means rotatable with the shaft when the shaft is rotated in a reverse direction to cam the valve closed over the vent, the slip-clutch cam means being adapted to slip relative to the shaft upon camming the valve closed so as to allow relative continued rotation of the shaft in the reverse direction.
 2. In a rotary tool as in claim 1, wherein the actuable means is a spring-returnable plunger.
 3. In a rotary tool as in claim 1, wherein the inlet is of restricted diameter relative to the vent.
 4. In a rotary tool as in claim 1, wherein the slip-clutch cam means is responsive to a change of rotation of the shaft from a reverse direction to said forward direction to rotate with the shaft so as to release the valve from its closed condition.
 5. In a rotary tool as in claim 4, wherein stop means projects into the path of rotation of the slip-clutch cam means so as to stop rotation thereof in said forward direction after the slip-clutch cam means has traveled a predetermined angular distance, the slip-clutch cam means being adapted to slip relative to the shaft when so stopped so as to allow relative continued rotation of the shaft in said forward direction.
 6. In a nut-running tool including a reversible rotary shaft, a pressure-operable signal device, an air-pressure chamber, and actuating means adapted upon building up of a predetermined air pressure within the chamber to cause operation of the signal device, the pressure chamber having an inlet connectable to a source of pressure air and having a vent for preventing buildup of inlet air pressure within the chamber when the vent is in open condition, a valve seat at the exit end of the vent, a ball valve having a loose relation to the seat while the shaft is rotating in a forward direction so as to allow venting of pressure air from the chamber; cam means for pressing the ball valve closed upon the seat when the shaft is caused to rotate in a reverse direction, slip-clutch means frictionally engaging the shaft with the cam means for rotation of the cam means with the shaft, the slip-clutch means adapted upon a predetermined resistance being offered to rotation of the cam means to allow rotative slippage of the shaft relative to the cam means, the ball valve adapted upon being pressed closed upon the seat by the cam means to resist further rotation Of the cam means by the shaft in said reverse direction.
 7. In a nut-running tool as in claim 6, wherein the slip-clutch means is responsive to a change of rotation of the shaft from a reverse direction to a forward direction so as to cause the shaft to carry the cam means angularly out of said pressed relation to the ball valve, an ear projects from the cam means, and a stop having cooperation with the ear following a predetermined angular movement of the cam means with the shaft resists further angular movement of the cam means with the shaft in the said forward direction. 